"Hagel is a statesman, and America has few of them," former U.S. ambassador to Iraq and Afghanistan Ryan Crocker wrote in a "Wall Street Journal" editorial this week.
"He knows the leaders of the world and their issues. At a time when bipartisanship is hard to find in Washington, he personifies it. Above all, he has an unbending focus on U.S. national security, from his service in Vietnam decades ago to his current position on the Intelligence Advisory Council," he said.
Obama defended Hagel in an interview last week, calling him a "patriot" who has done "extraordinary work" in public service, although he said he still had not made a final decision on who would head the Pentagon.
Other potential nominees for the DOD job include Michele Flournoy, former Under Secretary of Defense for Policy and a senior Obama campaign adviser for national security, and Ashton Carter, the current deputy secretary of defense.